﻿<p>Select type enabling the choice between
<em>IfcBooleanResult</em> and subtypes of
<em>IfcCsgPrimitive3D</em> as potential root tree expression at
<em>IfcCsgSolid</em>.</p>

<blockquote class="extDef">NOTE&nbsp; Definition from ISO
10303-42:<br>
This type identifies the types of entity which may be selected as
the root of a CSG tree including a single CSG primitive as a
special case.</blockquote>

<blockquote class="note">NOTE&nbsp; Corresponding STEP type
<strong>csg_select</strong> defined in ISO 10303-42.</blockquote>
<blockquote class="history">HISTORY&nbsp; New type in
IFC1.5.1.</blockquote>